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pythonpandasdataframerolling-computation

Pandas Rolling Function with Max

I have the following code:

import pandas as pd

# Sample DataFrame
df = pd.DataFrame({'clicks': [i for i in range(1000)]})

# Calculate the max of the next 140 rows for each row
roll = df['clicks'].rolling(window=141, min_periods=1).max()
print(roll)

Somehow it doesnt return the expected output:

0        141.0
1        142.0
2        143.0
3        144.0
4        145.0

But it outputs:

0        0.0
1        1.0
2        2.0
3        3.0
4        4.0

What do I do wrong?

Solution

  • You need to shift it by 140 rows forward so that the window includes the next 140 rows, and not just the first, second, third etc leading up to 999.

    # Calculate the rolling max of the next 140 rows for each row
roll = df['clicks'].shift(-140).rolling(window=141, min_periods=1).max()